Anatomic boundaries of the thorax limit the growth of the lungs. The thorax consists of the spine, the chondral and osseous ribs, and the sternum. Normally the spine and the ribs work together as a dynamic biomechanical structure to work efficiently at respiration. When a significant deformity of the thoracic cage exists, it changes the dynamics of this system, and can interfere with normal respirations and lung development. Thoracic Insufficiency Syndrome (TIS) is the inability of the thorax to support normal respiration or lung growth. TIS can occur in patients with congenital, infantile or neuromuscular scoliosis, congenital anomalies of the ribs, acquired chest wall deformities, and skeletal dysplasias. Malformations of the chest, spine or ribs can result in decreased thoracic volume and inadequate lung development or thoracic stiffness and lack of compliance.
There is no standard treatment for TIS associated with thoracic spine and rib cage deformity. Goals of treatment include optimizing conditions for growth and function of the thorax and lungs, maximizing spine length and minimizing spine deformity. Recently, one treatment option for patients with congenital scoliosis and fused ribs has been to perform an opening wedge thoracostomy operation with implantation in order to maintain expansion of the constricted hemithorax. Implants are then expanded every 4 to 6 months depending on growth rate. The implants currently available for this procedure have issues with migration, implant prominence, soft tissue breakdown, and infection.